Selective Hydrogenation Catalyst for Unsaturated Compound

ABSTRACT

The present invention relates to a selective hydrogenation catalyst for an unsaturated compound. The supported catalyst contains at least one Group VIB non-noble metal oxide and at least one Group VIII non-noble metal oxide deposited on a carrier; and the catalyst has an optimized acid distribution on the surface of the catalyst, and more preferably has an optimized Group VIII/VIB metal ratio and a Group VIII non-noble metal density per unit of catalyst surface area. Using the catalyst of the present invention can have the following advantages: the weight increase of light sulphides in an unsaturated compound or a mixture containing unsaturated compounds, the hydrogenation of a polyunsaturated compound, the isomerization of a monounsaturated compound, high operation flexibility and a significant improvement in the effects of a hydrogenation treatment.

FIELD OF TECHNOLOGY

The present invention relates to a selective hydrogenation catalyst foran unsaturated compound.

BACKGROUND ART

During a selective hydrogenation process for unsaturated compounds, theraw materials may contain certain amounts of sulphides in addition tothe unsaturated compounds, and all of the sulphides or portion of themare light sulphides. These light sulphides can react withpolyunsaturated compounds in the raw materials under the action of ahydrogenation catalyst to generate heavy sulphides, which can be removedby a process of fractionation.

The polyunsaturated compounds in the raw materials as described abovehave very unstable properties and are easy to be polymerized duringstorage and subsequent processing. Under the action of the hydrogenationcatalyst, a portion of the polyunsaturated compounds can be selectivelyhydrogenated into monounsaturated compounds.

At the time of hydrogenating the polyunsaturated compounds intomonounsaturated compounds, a small portion of the polyunsaturatedcompounds or monounsaturated compounds are hydrogenated into saturatedcompounds, and the occurrence of such reaction can be avoided as much aspossible by optimized design for the catalyst.

CN03815240.1 proposes a method for selective hydrogenation ofpolyunsaturated compounds into monounsaturated compounds using ahomogeneous catalyst. This method uses at least one salt of a transitionmetal element from Groups IB, IIB, VB, VIB, VIIB and VIII of theperiodic table, at least one ligand and at least one organometallicreducing agent.

CN200610064286.5 proposes a method of selective hydrogenation using acatalyst having controlled porosity. The method uses a catalyst on acarrier, comprising at least one metal from Group VIB and at least onenon-noble metal from Group VIII used in the sulphurized form, depositedon the carrier and having a controlled porosity, wherein: the weightcontent of Group VIB element oxide is necessarily higher than 12% byweight; the weight content of Group VIII element oxide is lower than 15%by weight; the sulphurization degree of metal components in the catalystis at least equal to 60%; and the pore volume having a diameter largerthan 0.05 microns in the catalyst is 10˜40% of total pore volume.

CN200610064287.x proposes a method for selective hydrogenation employinga sulphurized catalyst. The method uses a catalyst deposited on acarrier and comprising at least one metal from Group VIB and at leastone non-noble metal from Group VIII, wherein: the weight content ofGroup VIB element oxide is necessarily higher than 12% by weight; theweight content of Group VIII element oxide is lower than 15% by weight;the sulphurization degree of metal components in the catalyst is atleast equal to 60%; and the molar ratio of the non-noble metal fromGroup VIII to the metal from Group VIB is 0.2˜0.5 mole/mole.

CN200610064397.6 proposes a method of selective hydrogenation using acatalyst with a specific carrier. The method uses a supported catalystcomprising at least one metal from Group VIB and at least one non-noblemetal from Group VIII used in the sulphurized form, deposited on aspecific carrier comprising a metal aluminate of the MAl₂O₄ type with ametal M selected from nickel and cobalt.

CN200910170584.6 proposes a method for selective hydrogenation using asulphurized catalyst with a specified composition. The catalystcomprises at least one metal from Group VIB and at least one non-noblemetal from Group VIII supported on alumina, wherein: the Group VIB metaloxide is 4˜20% by weight of the catalyst; the Group VIII non-noble metaloxide is less than 15% by weight of the catalyst; the molar ratio of thenon-noble metal from Group VIII to the metal from Group VIB is 0.6˜3.0mole/mole; and the catalyst has a total pore volume of 0.4˜1.4 cm³/g.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a selectivehydrogenation catalyst for an unsaturated compound, which may result inincrease of light sulphides weight and isomerization reaction ofmonounsaturated compounds, in addition to selective hydrogenation.

A selective hydrogenation catalyst for an unsaturated compound, which isa supported catalyst, characterized in that at least one Group VIB metaland at least one Group VIII non-noble metal are supported on a carrier,wherein:

the amount by weight of the Group VIB element oxide is 4˜10%, preferably6˜8%;

the amount by weight of the Group VIII non-noble element oxide is 6˜15%,preferably 8˜12%;

-   -   the ratio B_(total)/L_(total) of B acid to L acid in the surface        acidity center of the catalyst is not more than 0.4, preferably        0.05˜0.3;

the ratio L_(weak)/L_(strong) of weak L acid to strong L acid in thesurface acidity center of the catalyst is 0.5˜2.0, preferably 0.5˜1.5;and

the carrier is or substantially is alumina.

In the present invention, the molar ratio of the Group VIII non-noblemetal oxide to the Group VIB metal oxide in the catalyst is preferablymore than 3.0 and equals to or less than 5.0 mole/mole, especially from3.2 to 5.0 mole/mole; the density of the Group VIII element per unitsurface area of the catalyst is not less than 8×10⁻⁴ g of Group VIIIelement oxide/m² of catalyst, especially not less than 10×10⁻⁴ g ofGroup VIII element oxide/m² of catalyst, by virtue of which the effectis better.

Under the action of the acidity center of a catalyst, the unsaturatedcompounds in processed raw materials tend to take polymerizationreaction to produce raw coke precursors such as colloids and the like,and these substances would cover the surface activity center of thecatalyst, impacting on the exertion of catalytic action. However, as forreaction of sulphides weight increase and isomerization reaction, thecatalyst is further required to have a certain acidity center. As aresult, in the design of a catalyst, in order to meet the requirementsof various reactions, it is necessary to adjust the constitution ofacidity center of the catalyst and distribution of strong, weak aciditycenters.

The methods for adjusting the ratio of B acid to L acid and the ratio ofweak L acid to strong L acid in the surface acidity center of thecatalyst are not limited in the present invention. Methods of thisaspect are also described in the book “Hydrogenation process andengineer”, China Petrochemical Press, for instance, modification ofcarriers by using non-metal oxides, hydrothermal treatment of catalystcarriers, and the like. The present invention could employ, but notlimited to, the methods described therein. Therefore, the composition ofa carrier is not particularly limited in the present invention, providedthat the ratio of B acid to L acid and the ratio of weak L acid tostrong L acid specified in this invention can be satisfied. The carrierrecommended in this invention is or substantially is alumina. Thecontent of alumina is preferably not less than 80 wt %, more preferablynot less than 90 wt %. According to different materials to be treated,variety of alumina can be selected in terms of crystal forms, total porevolumes and specific surfaces. Preferably, the crystal form of aluminais γ, δ, θ or a mixed crystal thereof. As for different carriercompositions, the adjustment method of the surface acidity centersthereof can be varied, which is a basic means of carrier modification.In addition to “Hydrogenation Technology and Engineering”, there arenumerous literatures that relate to methods for adjusting the surfaceacidity center of a carrier, such as those in CN102039151, CN1597093 andthe like. Thus, the requirement of a carrier to have a specific surfaceacidity center has been completely achieved in the prior art, andmanufacturers can provide corresponding products depending on the users'needs. For instance, a well-known method in the art is used to prepare acatalyst carrier: as needs, the carrier can be modified with non-metaloxides or precursors, and the resulting carrier can either be treatedwith water vapor at 400˜600° C. for 4˜6 h, or be calcinated at atemperature of 500˜700° C. or 700˜900° C. or 900˜1100° C. for 4˜6 h. Bythis method, the properties of the acidity center of the catalyst andthe distribution of strong/weak acid centers can be adjusted.Preferably, the total pore volume of the catalyst is 0.2˜0.5 cm³/g, morepreferably 0.2˜0.45 cm³/g, and most preferably 0.2˜0.39 cm³/g.Preferably, the specific surface of the catalyst is 50˜200 m²/g, morepreferably 50˜150 m²/g.

From the study on the hydrogenation reaction system of unsaturatedcompounds or mixtures containing the unsaturated compounds, theinventors found that the effect of hydrogenation treatment is improvednotably when the catalyst has the features defined according to thepresent invention.

Pyridine infrared analysis is used to analyze the acidity center of thecatalyst. This method is described in detail in “Modern Research Methodsof Catalysis” published by Science Press, in chapter 7, in-situ infraredspectroscopy. As for other parameters, well-known analysis andcalculation methods in the art are used.

Various technical means, such as tableting, mixing and kneading, ballmilling, extrusion, spraying-forming and the like, can be used toprepare a catalyst carrier. The catalyst carrier can be modified byvarious technical means to satisfy the requirement for the properties ofthe catalyst in this method.

The preparation method for a catalyst is not particularly limited in thepresent invention, and general impregnation methods can be employed, forexample, the salts of active components (nickel and/or molybdenum) canbe added into water or another solution, capable of forming complexes,to produce an active metal impregnating solution. The catalyst carrierwas impregnated in the active metal impregnating solution, and thendried at 120˜300° C. and calcinated at 400˜800° C.

The present invention increases the conversion rate and the selectivityfor hydrogenation of a polyunsaturated compound, and increases theisomerization ratio of a monounsaturated compound, by means of selectingactive components of a catalyst, optimizing acid distribution on thesurface of the catalyst, especially further selecting suitable GroupVIII/VIB metal ratio for the catalyst and a density of Group VIIInon-noble metal per unit surface area of the catalyst. Isomerizedolefins often have higher stabilities and octane values, which areusually very important to improve the properties of the unsaturatedcompounds or the mixtures containing the unsaturated compounds.

Like the prior art, when being used, the catalyst needs to besulphurized under the same sulphurization conditions as in the priorart, for example, metal oxides were conversed to sulfides. Typically,sulphurization is carried out under the following sulphurizationconditions: a pressure of 0.5˜3.0 MPa; a sulphurization temperature of200˜500° C.; a sulphurization space velocity of 0.5˜5.0 h⁻¹; and anatmosphere of hydrogen, hydrogen sulfide.

The conditions for using the catalyst can be: a pressure of 1.0˜5.0 MPa;a hydrogen/polyunsaturated compound molar ratio of 1˜20 mole/mole; aspace velocity of 2.0˜6.0 h⁻¹; and a temperature of 50˜250° C.

When the unsaturated compounds or the mixtures containing theunsaturated compounds are treated by using the catalyst of the presentinvention, the treatment is allowed to operate at a relative higherhydrogen/polyunsaturated compound molar ratio (e.g., more than 5.0), andthe degree by which the monounsaturated compounds are hydrogenated intosaturated compounds is very low, which results in large operationflexibility.

In a process of selective hydrogenation for unsaturated compounds,several reactions (included without limitation thereto) may take placeas follows:

(1) Addition Reaction of Polyunsaturated Compounds:

Since polyunsaturated compounds are highly active and tend to takeaddition reactions with other compounds to produce compounds havinglarger molecular weights. When sulfides, in particular light sulfides,are included in the reaction system, sulfides having higher boilingpoints can be produced by utilizing the addition reactions ofpolyunsaturated compounds, and such sulfides can be removed by a processof fractionation.

(2) Selective Hydrogenation of Polyunsaturated Compounds intoMonounsaturated Compounds:

Under the action of a catalyst, the polyunsaturated compounds can beselectively hydrogenated into monounsaturated compounds.

(3) Isomerization of Monounsaturated Compounds:

During the process of hydrogenation, monounsaturated compounds can takean isomerization reaction, which contributes to improve the stability ofthe monounsaturated compounds.

(4) Hydrogenation of Monounsaturated Compounds:

At the time of hydrogenation of polyunsaturated compounds intomonounsaturated compounds, a small portion of the monounsaturatedcompounds are hydrogenated into saturated compounds. In most instances,it is desirable for the monounsaturated compounds to be retained. As aresult, the monounsaturated compounds are required to be hydrogenated tominimum level by optimization of catalysts and conditions.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In the present invention, important technical parameters for evaluatingcatalyst performance are expressed as follows:

conversion rate of propanethiol %=(1−propanethiol content inproduct/propanethiol content in raw material)*100

conversion rate of dienes %=(1−dienes content in product/dienes contentin raw material)*100

conversion rate of monoenes %=(1−monoenes content in product/monoenescontent in raw material)*100

isomerization rate of monoenes %=isomerized olefins content/(isomerizedolefins content+alkanes content)*100

hydrogenation selectivity %=conversion rate of dienes/(conversion rateof dienes+conversion rate of monoenes)*100

Comparative Example 1

100 g of industrial grade SiO₂—Al₂O₃ powder (SiO₂ content: 14%) wasadded with 50 g of water, and then was subjected to kneading andextrusion molding. The resultant was then dried at 120° C. andcalcinated at 600° C. for 4 h to produce a catalyst carrier.

14 g of industrial grade ammonium molybdate was added into 45 g ofwater, and stirred to be dissolved. Next, 75 g of industrial gradenickel nitrate, 12 g of industrial grade citric acid were added theretoand stirred to be dissolved, to produce an active metal impregnatingsolution for catalyst.

The catalyst carrier was added into this impregnating solution,impregnated at normal temperature for 3 h. After that, the impregnatedcatalyst carrier was taken out and aged for 12 h, then dried at 120° C.and calcinated at 500° C. for 4 h to produce Catalyst A. This catalysthas a specific surface of 149 m²/g, a total pore volume of 0.41 cm³/g,MoO₃ content of 6.4% and NiO content of 10.6%. More data for propertyanalysis are shown in Table 1.

Comparative Example 2

100 g of industrial grade alumina powder was added with 50 g of water,and then was subjected to kneading and extrusion molding. The resultantwas then dried at 120° C. and calcinated at 500° C. for 4 h to produce acatalyst carrier.

14 g of industrial grade ammonium molybdate was added into 45 g ofwater, and stirred to be dissolved. Next, 75 g of industrial gradenickel nitrate, 12 g of industrial grade citric acid were added theretoand stirred to be dissolved, to produce an active metal impregnatingsolution for catalyst.

The catalyst carrier was added into this impregnating solution,impregnated at normal temperature for 3 h. After that, the impregnatedcatalyst carrier was taken out and aged for 12 h, then dried at 120° C.and calcinated at 500° C. for 4 h to produce Catalyst B. This catalysthas a specific surface of 240 m²/g, a total pore volume of 0.38 cm³/g,MoO₃ content of 6.4% and NiO content of 10.6%. More data for propertyanalysis are shown in Table 1.

Comparative Example 3

100 g of industrial grade alumina powder was added with 50 g of water,and then was subjected to kneading and extrusion molding. The resultantwas then dried at 120° C. and calcinated at 500° C. for 4 h, and wasfurther calcinated at 900° C. for 4 h to produce a catalyst carrier.

11 g of industrial grade ammonium molybdate was added into 80 g ofwater, and stirred to be dissolved. Next, 40 g of industrial gradenickel nitrate, 12 g of industrial grade citric acid were added theretoand stirred to be dissolved, to produce an active metal impregnatingsolution for catalyst.

The catalyst carrier was added into this impregnating solution,impregnated at normal temperature for 3 h. After that, the impregnatedcatalyst carrier was taken out and aged for 12 h, then dried at 120° C.and calcinated at 500° C. for 4 h to produce Catalyst C. This catalysthas a specific surface of 101 m²/g, a total pore volume of 0.38 cm³/g,MoO₃ content of 5.0% and NiO content of 5.8%. More data for propertyanalysis are shown in Table 1.

Comparative Example 4

100 g of industrial grade alumina powder was added with 50 g of water,and then was subjected to kneading and extrusion molding. The resultantwas then dried at 120° C. and calcinated at 500° C. for 4 h, and wasfurther calcinated at 900° C. for 4 h to produce a catalyst carrier.

30 g of industrial grade ammonium molybdate was added into 90 g ofwater, and stirred to be dissolved. Next, 30 g of industrial gradenickel nitrate, 12 g of industrial grade citric acid were added theretoand stirred to be dissolved, to produce an active metal impregnatingsolution for catalyst.

The catalyst carrier was added into this impregnating solution,impregnated at normal temperature for 3 h. After that, the impregnatedcatalyst carrier was taken out and aged for 12 h, then dried at 120° C.and calcinated at 500° C. for 4 h to produce Catalyst D. This catalysthas a specific surface of 101 m²/g, a total pore volume of 0.38 cm³/g,MoO₃ content of 11.0% and NiO content of 4.0%. More data for propertyanalysis are shown in Table 1.

Example 1

100 g of industrial grade alumina powder was added with 50 g of water,and then was subjected to kneading and extrusion molding. The resultantwas then dried at 120° C. and calcinated at 500° C. for 4 h, and wasfurther calcinated at 900° C. for 4 h to produce a catalyst carrier.

14 g of industrial grade ammonium molybdate was added into 45 g ofwater, and stirred to be dissolved. Next, 75 g of industrial gradenickel nitrate, 12 g of industrial grade citric acid were added theretoand stirred to be dissolved, to produce an active metal impregnatingsolution for catalyst.

The catalyst carrier was added into this impregnating solution,impregnated at normal temperature for 3 h. After that, the impregnatedcatalyst carrier was taken out and aged for 12 h, then dried at 120° C.and calcinated at 500° C. for 4 h to produce Catalyst E. This catalysthas a specific surface of 101 m²/g, a total pore volume of 0.38 cm³/g,MoO₃ content of 6.4% and NiO content of 10.6%. More data for propertyanalysis are shown in Table 1.

Example 2

100 g of industrial grade alumina powder was added with 50 g of water,and then was subjected to kneading and extrusion molding. The resultantwas then dried at 120° C. and calcinated at 500° C. for 4 h, and wasfurther treated in water vapor at 450° C. for 4 h to produce a catalystcarrier.

18 g of industrial grade ammonium molybdate was added into 45 g ofwater, and stirred to be dissolved. Next, 95 g of industrial gradecobalt nitrate, 16 g of industrial grade citric acid were added theretoand stirred to be dissolved, to produce an active metal impregnatingsolution for catalyst.

The catalyst carrier was added into this impregnating solution,impregnated at normal temperature for 3 h. After that, the impregnatedcatalyst carrier was taken out and aged for 12 h, then dried at 120° C.and calcinated at 500° C. for 4 h to produce Catalyst F. This catalysthas a specific surface of 97 m²/g, a total pore volume of 0.35 cm³/g,MoO₃ content of 9.1% and CoO content of 14.8%. More data for propertyanalysis are shown in Table 1.

Example 3

100 g of industrial grade SiO₂—Al₂O₃ powder (SiO₂ content: 1.4%) wasadded with 50 g of water, and then was subjected to kneading andextrusion molding. The resultant was then dried at 120° C. andcalcinated at 700° C. for 4 h to produce a catalyst carrier.

12 g of industrial grade ammonium molybdate was added into 120 g of 25%aqueous solution of ammonia, and stirred to be dissolved. Next, 75 g ofindustrial grade nickel nitrate was added thereto and stirred to bedissolved, to produce an active metal impregnating solution forcatalyst.

The catalyst carrier was added into this impregnating solution,impregnated at normal temperature for 1 h. After that, the impregnatedcatalyst carrier was taken out and aged for 12 h, then dried at 120° C.and calcinated at 500° C. for 4 h to produce Catalyst G. This catalysthas a specific surface of 96 m²/g, a total pore volume of 0.42 cm³/g,MoO₃ content of 6.3% and NiO content of 11.7%. More data for propertyanalysis are shown in Table 1.

Example 4

100 g of industrial grade SiO₂—Al₂O₃ powder (SiO₂ content: 7%) was addedwith 50 g of water, and then was subjected to kneading and extrusionmolding. The resultant was then dried at 120° C. and calcinated at 600°C. for 4 h to produce a catalyst carrier.

12 g of industrial grade ammonium metatungstate was added into 45 g ofwater, and stirred to be dissolved. Next, 75 g of industrial gradenickel nitrate, 12 g of industrial grade citric acid were added theretoand stirred to be dissolved, to produce an active metal impregnatingsolution for catalyst.

The catalyst carrier was added into this impregnating solution,impregnated at 60° C. for 30 min. After that, the impregnated catalystcarrier was taken out and aged for 12 h, then dried at 120° C. andcalcinated at 500° C. for 4 h to produce Catalyst H. This catalyst has aspecific surface of 142 m²/g, a total pore volume of 0.39 cm³/g, WO₃content of 7.0% and NiO content of 11.5%. More data for propertyanalysis are shown in Table 1.

Example 5

100 g of industrial grade TiO₂—Al₂O₃ powder (TiO₂ content: 3.5%) wasadded with 50 g of water, and then was subjected to kneading andextrusion molding. The resultant was then dried at 120° C. andcalcinated at 500° C. for 4 h, and was further calcinated at 700° C. for4 h to produce a catalyst carrier.

14 g of industrial grade ammonium molybdate was added into 45 g ofwater, and stirred to be dissolved. Next, 100 g of industrial gradenickel nitrate, 15 g of industrial grade citric acid were added theretoand stirred to be dissolved, to produce an active metal impregnatingsolution for catalyst.

The catalyst carrier was added into this impregnating solution,impregnated at normal temperature for 3 h. After that, the impregnatedcatalyst carrier was taken out and aged for 12 h, then dried at 120° C.and calcinated at 500° C. for 4 h to produce Catalyst I. This catalysthas a specific surface of 165 m²/g, a total pore volume of 0.28 cm³/g,MoO₃ content of 5.6% and NiO content of 13.2%. More data for propertyanalysis are as shown in Table 1.

TABLE 1 Composition and Physical properties of Catalysts A, B, C, D, E,F, G, H and I Catalyst No. Comparative Example Example 1 2 3 4 1 2 3 4 5A B C D E F G H I Carrier: SiO₂ Al₂O₃ Al₂O₃ Al₂O₃ Al₂O₃ Al₂O₃ SiO₂ SiO₂TiO₂ (20%)—Al₂O₃ (2%)—Al₂O₃ (10%)—Al₂O₃ (5%)—Al₂O₃ Total pore 0.41 0.380.38 0.38 0.38 0.35 0.42 0.39 0.28 volume cm³/g Specific 148 240 101 101101 97 96 142 165 surface m²/g MoO₃% 6.4 6.4 5.0 11.0 6.4 9.1 6.3 5.6NiO % 10.6 10.6 5.8 4.0 10.6 11.7 11.5 13.2 WO₃% 7.0 CoO % 14.8 Molarratio of 3.2 3.2 2.2 0.7 3.2 3.1 3.6 5.0 4.5 Group VIII metal/Group VIBmetal d_(Group VIII element oxide) 0.7 0.4 0.6 0.4 1.1 1.5 1.2 0.8 0.8(10⁻³ g/m²) B_(total)/L_(total) 0.47 0 0 0 0 0 0.06 0.28 0L_(weak)/L_(strong) 0.8 2.3 1.2 1.2 1.2 2.0 0.6 0.8 0.7

Among these catalysts, catalysts E, F, G, H and I are the catalysts ofthe present invention. In contrast, catalysts A, B, C and D do notbelong to the catalysts of the present invention.

INDUSTRIAL APPLICABILITY Example 6 Evaluation of Catalysts

A catalyst is charged into the middle part of a reaction tube having aninner diameter of 15 mm and a height of 320 mm, of which the upper andlower parts are filled with quartz sand of 20˜40 mesh for supporting.

The catalyst is sulphurized before use. The sulphurizing oil is amixture of cyclohexane and carbon disulfide (CS₂ content is 2%).Sulphurization conditions are: a pressure of 2.0 MPa; a liquid hourlyspace velocity of 4 h⁻¹; a hydrogen-to-oil volume ratio of 200:1; atemperature of 320° C.; and a sulphurization time of 12 h.

The mixture of unsaturated compounds for testing has the followingcomposition: 100 ppm by weight of propanethiol; 1% by weight ofpentadiene; 3% by weight of 1-heptylene; and balance of cyclohexane.

Hydrogenation treatment was performed under the conditions of a pressureof 2.0 MPa, a space velocity of 4 h⁻¹, a temperature of 120° C., and ahydrogen/diene molar ratio of 5:1. Next, the contents of propanethiol,dienes, monoenes, isomerized monoenes and alkanes in hydrogenatedproducts were analyzed.

Hydrogenation experiments were performed by using each of the catalystsof Comparative Examples 1˜4 and Examples 1˜5, and experimental resultsare obtained and shown in Table 2.

TABLE 2 Experimental results of respective Comparative Examples andExamples Catalyst No. A B C D E F G H I Conversion rate of 100 99.0 98.098.5 100 100 100 100 99.0 propanethiol % Conversion rate of 87.2 85.175.7 82.7 88.5 88.5 89.5 89.8 87.8 dienes % Isomerization rate 51.3 35.632.6 45.6 52.5 52.8 53.7 54.1 51.5 of monoenes % Hydrogenation 95.8 96.697.1 97.6 98.5 99.0 99.5 99.3 98.0 selectivity %

In the hydrogenation experiments of unsaturated compounds or mixturescontaining unsaturated compounds, the method of the present inventionhas higher conversion rates of propanethiol and dienes, andisomerization rates of monoenes and hydrogenation selectivities are alsoapparently higher than those of the method in the Comparative Examples.

Examples 7˜9

The experiment reactions were performed by using the Catalyst E inCatalyst Example 1, utilizing the same sulfuration method with feedstockof identical composition, and changing reaction conditions, theexperimental results obtained are as shown in Table 3.

TABLE 3 Experimental results of Catalyst E under different conditionsExample 6 7 8 Catalyst No. E E E Pressure MPa 1.5 2.0 3.0 Space velocityh⁻¹ 2.0 4.0 3.0 Temperature ° C. 100 120 110 Hydrogen/diene 10.0 5.015.0 molar ratio Conversion rate of 100 100 100 propanethiol %Conversion rate of 89.2 88.5 88.2 dienes % Isomerization rate 53.1 52.552.7 of monoenes % Hydrogenation 99.1 98.5 98.7 selectivity %

As can be seen from the above data, the catalyst illustrated in Example1 has a good adaptability. The hydrogenation treatment of unsaturatedcompounds with this catalyst can result in significantly high conversionrate of reaction products and selectivity in a wide range of conditions.

Examples 10˜12 Effect of Total Pore Volume

In accordance with the method of Example 1, three industrial gradealumina powders having different pore volumes were selected to preparecatalysts respectively, resulting in Catalysts E, J, and K. The majordistinction among these three catalysts is being different in total porevolume. The total pore volumes of Catalysts E, J, and K are 0.38 cm³/g,0.28 cm³/g, and 0.55 cm³/g, respectively. The catalysts were evaluatedby the method of Example 6, and resulting experimental results are asshown in Table 3.

TABLE 3 Effect of total pore volume of catalyst Example 10 11 12Catalyst No. E J K Conversion rate of 100 100 100 propanethiol %Conversion rate of 88.5 88.7 88.2 dienes % Isomerization rate 52.5 53.548.7 of monoenes % Hydrogenation 98.5 99.3 97.2 selectivity %

As can be seen from the experimental data, when the total pore volume ofa catalyst is suitably reduced, the selectivity of hydrogenation for anunsaturated compound is further improved.

When the catalyst of the present invention is used to hydrogenateunsaturated compounds, the effect of hydrogenation treatment is improvednotably. The catalyst of the present invention has higher conversionrate of thiols, higher saturation rate of dienes and betterhydrogenation selectivity for dienes as compared to other catalysts.

1. A selective hydrogenation catalyst for an unsaturated compound, whichis a supported catalyst, comprising at least one Group VIB metalcomponent and at least one Group VIII non-noble metal componentsupported on a carrier, wherein: the Group VIB metal component comprisesa Group VIB metal oxide in an amount of from 4% to 10% by weight of thecatalyst; the Group VIII metal component comprises a Group VIIInon-noble metal oxide in an amount of from 6% to 15% by weight of thecatalyst; the catalyst comprises a B_(total)/L_(total) ratio of B acidto L acid in a surface acidity center of not more than 0.4; and aL_(weak)/L_(strong) ratio of weak L acid to strong L acid in the surfaceacidity center of 0.5 to 2.0; and the carrier is substantially alumina.2. The selective hydrogenation catalyst according to claim 1, whereinthe Group VIII non-noble metal oxide and the Group VIB metal oxide arein a molar ratio of from greater than 3.0 mole/mole to 5.0 mole/mole;and the Group VIII metal oxide per unit surface area of the catalyst is8×10⁻⁴/m² of greater.
 3. The selective hydrogenation catalyst accordingto claim 2, wherein the molar ratio of the Group VIII non-noble metaloxide to the Group VIB metal oxide in the catalyst is from 3.2 mole/moleto 5.0 mole/mole.
 4. The selective hydrogenation catalyst according toclaim 1, wherein the Group VIB metal component comprises molybdenum,tungsten, or combinations thereof.
 5. The selective hydrogenationcatalyst according to claim 1, wherein the Group VIII non-noble metalcomponent comprises nickel, cobalt, or combinations thereof.
 6. Theselective hydrogenation catalyst according to claim 1, wherein the GroupVIB metal oxide is in an amount of from 6% to 8% by weight of thecatalyst.
 7. The selective hydrogenation catalyst according to claim 1,wherein the Group VIII non-noble metal oxide is in an amount of from 8%to 12% by weight of the catalyst.
 8. The selective hydrogenationcatalyst according to claim 1, wherein the Group VIII metal oxide perunit surface area of the catalyst is 10×10⁻⁴/m² or greater.
 9. Theselective hydrogenation catalyst according to claim 1, wherein the ratioB_(total)/L_(total) of B acid to L acid in the surface acidity center ofthe catalyst is from 0.05 to 0.3.
 10. The selective hydrogenationcatalyst according to claim 1, wherein the ratio L_(weak)/L_(strong) ofweak L acid to strong L acid in the surface acidity center of thecatalyst is from 0.5 to 1.5.
 11. The selective hydrogenation catalystaccording to claim 1, comprising a total pore volume of from 0.2 to 0.5cm³/g.
 12. The selective hydrogenation catalyst according to claim 1,comprising a specific surface of from 50 to 200 m²/g.
 13. The selectivehydrogenation catalyst according to claim 1, wherein the amount ofalumina in the carrier is not less than 80 wt %.
 14. The selectivehydrogenation catalyst according to claim 1, wherein the aluminacomprises a crystal form selected from γ, δ, θ, and combinationsthereof.
 15. The selective hydrogenation catalyst according to claim 1,wherein the Group VIB metal component comprises molybdenum.
 16. Theselective hydrogenation catalyst according to claim 1, wherein the GroupVIII non-noble metal component comprises nickel.
 17. The selectivehydrogenation catalyst according to claim 1, comprising a total porevolume of from 0.2 to 0.45 cm³/g.
 18. The selective hydrogenationcatalyst according to claim 1, comprising a total pore volume of from0.2 to 0.39 cm³/g.
 19. The selective hydrogenation catalyst according toclaim 1, comprising a specific surface of from 50 to 150 m²/g.
 20. Theselective hydrogenation catalyst according to claim 1, wherein theamount of alumina in the-carrier is not less than 90 wt %.